They included supporters of opposition leaders Mr Mousavi and Mehdi Karroubi, and aides of Mr Khatami.

The semi-official Fars news agency reported that former deputy foreign minister Mohsen Aminzadeh, former government spokesman Abdollah Ramazanzadeh, former senior lawmaker Mohsen Mirdamadi and former Industry Minister Behzad Nabavi were among those on trial.

The BBC's Kasra Naji says the timing and scale of the trial came as a surprise and suggests Iran's leadership wants to send a message to stop any more protests.

Foreign media, including the BBC, have been restricted in their coverage of Iran since the election protests turned into confrontations with the authorities in which at least 30 people were killed.

Opposition groups alleged widespread vote-rigging. Post-election protests saw the largest mass demonstrations in Iran since the 1979 revolution, which brought about the current Islamic system of government.

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